1. Field of the Invention
The present invention relates to a direct injection injector for an engine, and more particularly, to a structure of an injector directly injecting fuel for combustion of the engine into the combustion chamber.
2. Description of Related Art
Direct injection injectors that directly inject fuel into the combustion chamber of an engine falls into an inward type where an needle assembly moves inside the injector and an outward type where injector moves outside, in injection.
As for the inward type of injectors, the inside of the end of the injector is exposed to flame in the combustion chamber and caulking in which the nozzle of the injector is clogged due to contamination of the end of the injector by soot generated after combustion may occur, such that the injection pressure of the fuel is increased to prevent the nozzle from clogging up.
Meanwhile, the outward type of injector is shown in FIG. 1, where since a needle assembly 500 moves outside an injector 502, a ring with a predetermined space is formed between the outside of injector 502 and needle assembly 500 and the ring function as a nozzle injecting fuel, such that the fuel is injected in a cone shape, and needle assembly 500 moves outward, such that it is possible to prevent the nozzle from cogging with soot.
However, the nozzle that is open for fuel injection in injector 502 is formed in a considerably large conical shape, when fuel fails to be injected at high pressure in the outward type of injector 502, the size of droplet of the fuel is not sufficiently decreased, such that the fuel and air cannot be sufficiently mixed.
That is, when the fuel fails to be injected at high pressure, caulking is caused in the inward type and there are problems in the spray type and the size of droplet of the fuel in the outward type.
The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.